Device to be mounted on a boat to enable to launch and to retrieve the boat from and into water, boat equipped with such a device and corresponding harbour facility

ABSTRACT

A device mounted on a boat to launch and retrieve the boat from and into water and to drive it on solid ground, comprising a first set including at least one wheel that pivots freely and mounted on a holder in the stem area of the boat, and two second sets each including at least one drive wheel mounted on a holder in the rear area of the boat, with one of the second sets on the port side and the other on the starboard side, said sets being arranged to place the at least one free wheel in the front and the drive wheels in the back on the ground to roll on solid ground and to launch and retrieve the boat from and into water, said sets being adjustable so that the drive wheels come into contact with a slip before the at least one free wheel.

CROSS REFERENCE TO RELATED APPLICATIONS

Patent applications covering the subject-matter of the present US patentapplication were filed with the French Patent Office on Jul. 8, 2009under the application number 0903377 and with the European Patent Officeon Jul. 8, 2010 under the application number 10168919.8.

BACKGROUND OF THE INVENTION

The invention relates to the field of shallow draft boats, in particularthose having a small size, especially boats 7-8 metres long.

The invention firstly relates to a device to be mounted on a boat,enabling to launch and to retrieve the boat from and into water.

This device can come in the form of a kit composed of different setscarrying wheels that the user will place on the outside of the hull soas to be able to make the boat roll on solid ground and to launch itinto water, remove from the boat for navigation, and replace when itcomes back on solid ground, such a kit being therefore particularlyintended to equip the existing boats.

Otherwise, the device can come in a built-in form or with thepossibility of being built into the boat, which has, inside its hull,housings or casings for the sets carrying the wheels, these beingretractable in the hull for navigation and extended to get the wheelsout in order to make the boat roll on solid ground, launch it into waterand retrieve it from water.

The invention also relates to a boat which is equipped or suitable forbeing equipped in this way.

Lastly, the invention relates to a harbour facility provided with awater entry and exit slip and a parking area for the boats carrying thedevice according to the invention, the position of the wheels of thelatter being in particular adjusted depending on the slope of this slip.

In most cases, the owner of a pleasure boat only makes a few trips atsea of his/her boat. Otherwise, the boat is not used and has to be leftin a safe place.

Currently, there are two solutions for boat parking: into water or indry dock.

The first solution consists in leaving the boat into water in arecreational harbour's location rented by the year. However, the numberof locations of a recreational harbour is very restricted and it isoften necessary to wait for several years after the renting applicationfor a location to get it. Another drawback is the extremely high costfor renting a location, added to the insurance and boat caretaking cost.

Furthermore, the boat being constantly into water, a corrosion of thefittings cannot be avoided, resulting in costly servicing operations. Itis also necessary to apply an antifouling paint for preventing marineorganism deposit on the boat hull which would occur otherwise.Antifouling paints are naturally toxic and therefore harmful for humanbeings and the marine environment.

A second solution consists in retrieving the boat from water and in drystoring it, either in boat dry storage automatic systems orconventionally in a garage, by placing the boat on a trailer.

To retrieve the boat from water and to launch it again into water, it ispossible to use an automatic boat elevator, which can lift the boat outof water and dry position it, either on a trailer or in a boat drystorage automatic system, and which can lift the boat and move it so asto launch it into water.

The owner is therefore forced to reserve the elevator in advance, for agiven schedule, for launching and/or retrieving his/her boat from andinto water. The use of the boat is therefore restricted and the ownerloses a part of his/her freedom of using the boat. Thus, he/she cannotextend a trip at sea, for example if the navigation conditions areparticularly nice, because then, he/she will not be able to retrievehis/her boat from water. Further, the cost for using an elevator ishigh.

The owner can also launch and retrieve his/her boat from and into waterhimself/herself. For launching the boat into water, the boat beingplaced on a trailer connected to the rear of the owner's vehicle, theowner first has to make the boat reverse on the slip in order to placethe trailer into water as much as possible.

If the owner is accompanied by a person, the owner, or this person, getson the boat, and the person, or the owner, detaches the boat from thetrailer, the boat then floating. The person ashore then has to park thevehicle with the trailer in a parking space and, if he/she takes part inthe trip at sea, go to a pontoon to which the person on board the boatbrought the boat.

If the owner is alone, he/she has to detach the boat from the trailerand get on the boat directly. Then, he/she has to moor the boat to apontoon, and then come back to the boat launch slip so as to fetch thevehicle and the trailer and park them in a parking area.

For retrieving the boat from water, the owner has to be helped by aperson. If this person is on board the boat with the owner, first he/shehas to get off the boat at a pontoon, and then go to fetch the vehicleand the trailer to place them on the boat retrieval slip, with thetrailer being placed into water as much as possible.

The person on board the boat leads the latter until the boat retrievalslip and causes the boat to come on the trailer, the boat being liftedby the trailer. Once it has been placed on the trailer, the personashore attaches the boat to the trailer and the boat can be towed out ofthe boat retrieval slip.

As it can be noticed, these boat launching and retrieving manoeuvres aredifficult, due to the slip slope, the slip surface quality makingdriving the vehicle on it difficult, etc. It is also to be noticed thatit is extremely difficult to retrieve a boat from water alone.

BRIEF SUMMARY OF THE INVENTION

The present invention aims to overcome the aforementioned problems.

Consequently, it first relates to a device to be mounted on a boat toenable to launch and to retrieve the boat from and into water through aboat launch and retrieval slip and to drive it on solid ground, whereinit comprises:

-   -   a first set constituted by at least one freely pivotable wheel        or group of freely pivotable wheels mounted on a holder to be        mounted in the stem area of the boat; and    -   two second sets each constituted by at least one drive wheel        mounted on a holder to be mounted in the rear area of the boat,        with one of the second sets on the port side and the other on        the starboard side,        said sets being arranged so that, when they are mounted in the        stem area and on the port side and on the starboard side,        respectively, the at least one free wheel in the front and the        drive wheels in the back are placed on the ground, in order to        make the boat roll on solid ground and to launch and retrieve it        from and into water, said sets being adjustable so that, when        the boat is retrieved from water, the drive wheels come into        contact with said slip before the at least one free wheel, said        sets being further retractable in order to leave the boat hull        free for navigation, means being provided for the control of the        drive wheels.

In accordance with a first embodiment, the holders of the first set andsecond sets each are provided, on the one hand, with adjustable mountingmeans on the outside of the boat hull, which is provided withcomplementary means for receiving said holders, and, on the other hand,with means enabling the user to remove each of the sets from the boatonce the latter has been launched into water and to bring them back intothe boat, and then to mount them again from the boat in preparation forthe arrival on the slip leading to solid ground, the holder of the firstset consisting in a so-called stem bar, which is to be positioned alongthe boat stem line, which may go down to the keel, and fit the stemcurvature, and to which is connected a pivot axis of the at least onefree wheel, and the holder of each second set consisting in a so-calledtidal leg carrying at its base its associated at least one drive wheel.Advantageously, the holder of the first set comprises means for dampingthe boat weight on the at least one free wheel and the holder of eachsecond set comprises means for damping the boat weight on the at leastone drive wheel.

The first set and/or the second sets are advantageously arranged so asto be able to float in case the user makes them fall into water. Inparticular, the first set and/or the second sets are provided with atleast one float so as to float into water.

In accordance with a particular implementation of the device of theinvention, the stem bar includes a front bar and a rear bar which arepivotable with respect to each other so as to fit the boat stemcurvature by extending down to the keel, at least one of the bars beingadjustable in length so as to adapt to the boat sizes, at least one ofthe bars being edged by shims in order to better fit the stem shape.Optionally, the stem bar carries floats externally, on the front bar orthe rear bar, or on both. Optionally, the at least one bar adjustable inlength is edged by lateral wings linked by transverse rollers freelyrotatable so as to ensure stem bar positioning and locking.

Alternatively, the stem bar is formed by a chain, consisting insuccessive flat links hinged one to another, at least one flat linkbeing foldable along its free borders in order to form shims allowing tobetter fit the shape of the stem.

Alternatively, the stem bar consists in a curved-shape one-piece bar,whose curve fits the stem curve of the boat to be equipped with thedevice.

In particular, the stem bar can have means for adjusting thelongitudinal position of the at least one free wheel, allowing to adjustthe position of the at least one free wheel such that, when the boatequipped with said device arrives on a boat retrieval slip, the drivewheels of the tidal legs first touch the boat retrieval slip. Theseadjusting means may consist in particular in a series of spaced-apartholes in which the pivot axis of the at least one free wheel can come inorder to secure the at least one free wheel to the stem bar.

Also, the stem bar can be provided, at its stem side end, with a meansfor its securing to the boat, such as a screw securing means for asecuring to a ear stem plate, as well as with a handle that the user cangrip to bring the stem bar back on board, and is provided with, at itskeel side end, at least one passage for at least two lines or atightening strap for maintaining the stem bar against the stem.

In case of use of at least two lines, at least one line is on the portside and at least one line is on the starboard side and a first end ofeach of the at least two lines is received in said at least one passageand attached there to the stem bar. The other end of the at least twolines, opposite to said first end, advantageously carries floats and isadvantageously arranged to cooperate with turnbuckles installed on theboat and allowing to permanently adjust the length of said lines orstraps.

In case of use of a tigthening strap, said at least one passage consistsin a ring carried by the stem bar, advantageously by the underside ofthe stem bar, and in which is threaded the tigthening strap. When thestem bar is to be maintained against the boat stem, a first end of thetightening strap is removably attached to a first border area of theboat, optionally using attaching means carried by said end of thetightening strap or using attaching means carried by the boat, and thesecond end of the tightening strap, opposite to said first end, isattached to the border area of the boat, opposite to said first borderarea, in a manner allowing to tighten the strap around the hull once thefirst end has been attached to the first border area, so as to securelymaintain the stem bar against the boat stem. To that end, the second endof the tightening strap may optionally carry tightening attaching means,such as ratchet and cam buckle tensioning assembly. Two stopping means,such as stopping rings, may be made integral with the tightening strap,on either side of the stem bar, after the tightening strap has beenthreaded in said at least one passage, so as to prevent the strap fromescaping out of the stem bar.

Each leg can include:

-   -   a fixed body;    -   a moving body moveable with respect to the fixed body for        damping the uneven ground when the boat rolls on solid ground,        and provided with bearing means arranged to support the boat;    -   the at least one drive wheel connected to the fixed body;    -   an engine driving the at least one drive wheel and controlled by        said control means;    -   securing means for securing the driving tidal leg to the boat;        and    -   at least one carrying and/or gripping handle for the boat        launch.

Alternatively, each leg can include:

-   -   a single body;    -   the at least one drive wheel connected to the single body;    -   an engine driving the at least one drive wheel and controlled by        said control means;    -   securing means for securing the driving tidal leg to the boat;        and    -   at least one carrying and/or gripping handle for the boat        launch.

Optionally, the leg includes, associated to the engine, a brakingdevice, such as a braking device with a ratchet wheel and a pawl. Theleg may also carry at least one float.

If the device is intended to be used with rigid-hull-type boats, it isadvantageously provided that:

-   -   the legs are arranged to each be placed on a lateral side of the        boat hull, symmetrically with respect to the longitudinal median        plane of the boat;    -   the bearing means are constituted by a support platform leaning        against the boat hull when the device is in mounted position, in        order to support the boat, the position in height and in depth        of the support platform with respect to the moving body being        adjustable so as to fit to the hull curvature; and    -   the means for securing the leg to the boat are constituted by a        threaded rod extending from the leg and passing through a hole        made in the boat hull and cooperating with a nut in order to        lock the driving tidal leg against the boat hull, or are        constituted by a bracket to be placed on the edge of the boat        and means for removably securing the upper portion of the leg        body to the outer face of the bracket in mounted position        thereof.

If the boat is intended to be used with pneumatic-type boats, the sidesof which are constituted by sponsons connected by a rear panel carryingan engine, it is advantageously provided that:

-   -   the legs are arranged to be secured to the rear panel, on each        side of the engine;    -   the bearing means are constituted by a bearing piece secured to        the rear panel and comprising an area protruding from a first        surface of the bearing piece in order to create a shoulder, the        end face of the protruding area coming into contact with the        rear panel in the mounted position, and by a support block which        is secured to the leg moving body and having, on its upper edge,        a groove receiving the shoulder of the bearing piece in order to        support the boat; and    -   the means for securing the leg to the boat are constituted by a        connection block to be secured to the moving body of a two-part        body or to the single body and provided with a threaded hole        receiving a bolt passing through a through hole made in the rear        panel in order to secure the connection block to the boat, the        position in height of the connection block with respect to the        moving body of a two-part body or to the single body being        adjustable.

In accordance with a second embodiment of the device according to theinvention, the first set and the two second sets are built into a boatand are retractable in casings formed in the hull, said sets beingprovided with means for mounting their holders in said casings and meansfor controlling their extension out of said casings so as to positionthe wheels in a position for making the boat roll on solid ground andfor launching and retrieving it from and into water, and theirretraction in the casings to leave the boat hull free for navigation.

In every instance, the means for controlling the drive wheels areadvantageously hand-held control means or control means applied to theinstrument panel.

The invention also relates to a boat which is equipped or ready to beequipped permanently with the device as defined above.

The invention also relates to a method for initially adjusting thedevice according to the invention, wherein it comprises the followingsteps:

-   -   the boat is placed on legs such that its true waterline, which        is painted on its hull, is horizontal;    -   the second sets and the first set are positioned on the boat;    -   the slope of the boat launch slip of the harbour facility is        physically represented by a line B, for example using a cord;    -   the height of the drive wheels and of the at least one free        wheel are adjusted with respect to this line B to ensure that        the drive wheels will come into contact with the slip before the        at least one free wheel.

The initial adjustment of the device will generally depend on the boatit is intended to equip and on the slope of the boat launch andretrieval slip of the harbour facility which will be frequented.

Lastly, the invention relates to a harbour facility for receiving boatsequipped with a device as defined above and boats equipped or ready tobe equipped permanently with the device as defined above, in order toallow parking thereof, said harbour facility comprising a boat launchand retrieval slip leading to a boat ground parking area, the sliphaving a slope for which the means for driving the boats were adjustedso that the drive wheels of the rear drive means touch the boatretrieval slip first, said harbour facility also comprising an area forreceiving the boats once they have been retrieved from water. Theharbour facility advantageously comprises a parking area constituted byparking spaces.

The slip slope is advantageously of 4-6°, in particular of 5°, in orderto ensure a good grip of the drive wheels when they arrive on the slipwhile getting out of water.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

To better illustrate the subject-matter of the present invention,particular embodiments thereof will be described hereinafter withreference to the accompanying drawing.

On this drawing,

FIG. 1 is a perspective view of a rigid-hull-type boat, equipped with adevice according to a first embodiment of the invention, which comes inthe form of a kit, the boat being depicted by dash and dot lines and thekit members being depicted in an exploded view in the position they willoccupy on the hull once they have been mounted;

FIG. 2 is, at a bigger scale, an exploded perspective view of the stembar-free wheel set of the kit in FIG. 1;

FIG. 3 is an elevation view of a driving tidal leg set of the kit inFIG. 1;

FIGS. 4A to 4C are side views of a boat respectively during first tothird adjusting steps of the kit in FIG. 1;

FIG. 5 is a perspective view of a boat into which is built the deviceaccording to the invention, in accordance with a second embodiment;

FIG. 6 is a perspective view of a harbour facility in which boatsequipped with the device according to the invention can be parked;

FIG. 7 is a perspective view of a pneumatic-type boat, which is equippedwith a kit according to the invention, constituting an alternative ofthe one in FIG. 1 for pneumatic boats;

FIG. 8 is an exploded perspective view of a driving tidal leg of the kitdepicted in FIG. 7

FIG. 9 is a schematic side view of the pneumatic boat of FIG. 7, with astem bar made in accordance with an alternative;

FIG. 10 is a perspective view of an alternative driving tidal leg set ofthe kit of FIG. 1;

FIGS. 11 and 12 depict in exploded perspective view and in the mountedstate, respectively, an alternative mode for the securing of the drivingtidal leg set of the kit of FIG. 1; and

FIG. 13 is a perspective view of an alternative stem bar-free wheels setof the kit of FIG. 1.

DETAILED DESCRIPTION OF THE INVENTION

With reference to FIG. 1, it is illustrated a rigid-hull-type boat 1 onwhich is installed a kit-type removable device 2 according to a firstembodiment of the invention.

The removable device 2 includes a first set constituted by a stem bar 3placed under the boat stem and extending down to the keel and carryingfree wheels 33, and two second sets each constituted by a driving tidalleg 4 which will be described more in detail hereinafter, the legs 4being placed on each side of the boat in the stern area, a controldevice 5 being arranged in the pilot house to enable to control the legs4.

With reference now to FIG. 2, it can be seen that the stem bar 3includes a front bar 31 and a rear bar 32.

The front bar 31 includes a U-shaped plate 311 in which afull-bar-shaped moving portion 312 slides.

Each side wall of the U-shaped plate 311 is provided with a first row ofholes 313 which are spaced apart from each other by a constant pitchalong the longitudinal direction of the U-shaped plate 311. These firstrows of holes 313 are located at the same height such that each hole 313of a side wall corresponds to a corresponding hole 313 on the oppositeside wall.

Through holes 312 a are made in the moving portion 312 and they arespaced apart from each other in the longitudinal direction of the movingportion 312 by a pitch which is equal to that of the row of holes 313.

The arrangement of these different holes 313 and 312 a allows adjustingthe position of the moving portion 312 in the U-shaped plate 311, andtherefore the length of the stem bar 3. Indeed, the moving portion 312can slide in the U-shaped plate 311 and be locked in position using abolt (not shown) passing through a hole 313 of a first side wall of theU-shaped plate 311, the corresponding through hole 312 a and thecorresponding hole of the second side wall of the U-shaped plate 311.

It can also be seen that the free end of the moving portion 312 ends inan axis 315 having a central opening 315 a into which a pin 316 acooperating with a dowel pin 316 b is placed. The axis 315 carries ahandle 315 b enabling to handle the stem bar 3, particularly from theboat.

A second row of holes 317 is provided on each side wall of the U-shapedplate 311, which rows of holes 317 are located above the respective rowsof holes 313 and are parallel thereto. These second rows of holes 317are located at the same height such that each hole 317 of a side wallcorresponds to a corresponding hole 317 on the opposite side wall.

Rollers 318 are arranged in the U-shaped plate 311 through axis (notshown) passing through a central opening made in each roller and eachend of an axis lying in a hole 317 in order to be integral with theU-shaped plate 311. The sizes of the axis and of the central openingsinto which are inserted the axis are such that the roller can rotatefreely with respect to the axis. The rollers 318 promote the stem bar 3positioning and locking against the stem line.

It is also to be noted that the row of holes 313 is spaced apart fromthe row of holes 317 such that the moving portion 312 can slide in theU-shaped plate 311 without being blocked by the rollers 318.

The front bar 31 is connected by a hinge 31 a to the rear bar 32 inorder to be pivotable with respect to the latter. The rear bar 32 is afull bar in which a first row of through holes 321 and a second row ofthrough holes 322 are made.

The through holes 321 are made in the vertical direction and are spacedapart from each other along the longitudinal direction of the rear bar32.

The holes 322 are made transversally, their role being indicatedhereinafter.

A group of two free wheels 33 linked by their axle is mounted on avertical axis 331 passing through the rear bar 32 through one of thethrough holes 321 and is pivotable by 360° around this axis and can rollon the ground when the stem bar 3 mounted on the boat hull.

There could be only one free wheel 33 mounted on the vertical axis 33′and freely pivotable by 360°.

A damping block 332 or “silent block” is intended to absorb thevibrations which are generated when the free wheels 33 roll on theground.

Providing a row of through holes 321 along the longitudinal direction ofthe rear bar 32 allows to adjust the position of the free wheels 33.

It can also be seen that, against the side walls of the front bar 31 andof the rear bar 32, are affixed two pairs of tilted side plates or shims319 widening upwards in mounting position. Each shim 319 is connected tothe front bar 31 or to the rear bar 32 by a hinge (not shown) in orderto be pivotable with respect to the front bar 31 or to the rear bar 32and to be secured at a given slope. These shims 319 allow to fit thestem bar 3 against the hull.

With reference again to FIG. 1, it can be seen that the stem bar 3 isplaced under the boat 1 so as to extend approximately from the keel tothe stem. The stem bar 3 is positioned in such a way that the connectionbetween the front bar 31 and the rear bar 32 is located at thetransition between the keel and stem of the boat 1.

The fact that the front bar 31 can pivot with respect to the rear bar 32allows the stem bar 3 to globally fit the specific curvature of the hullof the boat 1, which can vary from boat to boat.

The stem bar 3 is advantageously provided with at least one float 35 inorder to ensure the stem bar 3 floatation, two floats 35 being shown inFIGS. 1 and 2, one under the front bar 31, the other under the rear bar32. The technical features of the floats 35 are defined with respect tothe stem bar 3 mass, in order to ensure a sufficient floatation of thelatter.

An end plate 34 provided with ears 34 a is secured to the boat stem byscrews 34 b such that the ears 34 a extend from the stem. This platecould be a plate already present on the boat and therefore already usedfor other purposes. However, it is preferable that the kit according tothe invention includes this plate 34 which is intended to be secured onthe stem so as to receive the stem bar 3 provided with its group of freewheels 33 (or with its free wheel 33).

The length of the front bar 31 is adjusted by sliding the moving portion312 in the U-shaped plate 311 such that the axis 315 is positionedbetween the ears 34 a, enabling the pin 316 a to pass through the ears34 a and the through hole 315 a and to extend from them in order toenable the dowel pin 316 b to lock the pin 316 a.

The front end of the stem bar 3 is thus secured to the boat 1. The rearend of the stem bar 3 is pinned against the keel using two lines 323, afirst end of each line 323 being secured to the rear bar 32 via throughholes 322 and the other end being secured to the boat 1. Both lines 323can thus be arranged in two opposite holes 322 selected along the bar32.

Several lines 323 secured in different holes 322 can also be provided.

In the vicinity of the points of securing the lines 323 to the boat 1,turnbuckle systems for the boat can advantageously be installed so as topermanently adjust the length of the lines 323. The end of the lineswhich is opposite to the securing end on the stem bar 3 isadvantageously formed into an eyelet to be inserted in a turnbuckle. Aline is advantageously provided with a float, just before each eyelet.The lines on the port side and on the starboard side are advantageouslymarked with colours, respectively green and red, this code beingunderstood by boaters.

With reference now to FIG. 3, it is shown an elevation view of a setconstituted by a “tidal leg”-type leg which carries at its base a drivewheel 43 and which is sometimes called a “driving tidal leg”hereinafter. This driving tidal leg 4 includes a fixed body 41 and ahollow moving body 42, in which an upper portion of the fixed body 41 isaccommodated.

The drive wheel 43 is mounted integrally with a shaft 44 extending inthe lower portion of the fixed body 41 and connected to it by bearingsso as to be able to rotate.

The shaft 44 carries a ratchet wheel 45 carrying on its peripherynotches causing the rise of a pawl 46 during a rotation in the directioncorresponding to the forward movement of the boat, but locked by thepawl 46 in the other direction. The pawl 46 is connected to a controlmechanism allowing, if needed, to maintain it disengaged from thenotches whatever the ratchet wheel 45 rotation direction is.

An electric motor 47, integral with the fixed body 41, drives the shaft44 to rotate, for example via a belt.

The moving body 42 and the fixed body 41 are connected via a dampingblock 42 a, enabling the moving body 42 to slightly move with respect tothe fixed body so as to damp the vibrations generated when the boatmoves on the ground.

A threaded rod 42 b projects from the upper portion of the moving body42 in order to extend through a hole 42 g made in the boat 1 hull whenthe driving tidal leg 4 is in position of use. This threaded rod 42 bcooperates with a nut 42 c for securing in position the driving tidalleg 4 to the boat 1.

The moving body 42 also has a boat launch handle 42 d and a carryinghandle 42 e.

Further, a support platform 48 comes to fit to the moving body 42 inorder to enter into contact with the boat 1 hull when the driving tidalleg 4 is in position of use. The support platform 48 includes a L-shapedplate 48 a and two connection blocks 48 b.

Both connection blocks 48 b extend from the L-shaped plate 48 a in orderto make the support platform 48 integral with the moving body 42. Forthis purpose, each connection block 48 b has through holes 48 c arrangedin rows and in columns. The moving body 42 has a column of threadedholes 42 f on each side thereof. A screw (not shown) makes the supportplatform 48 integral with the moving body 42 by screwing in a throughhole 42 c and a threaded hole 42 f.

Providing for columns and rows of through holes 48 c allows anadjustment of the support platform 48 in depth and in height,respectively.

Thus, the position of the support platform 48 can be modified so as tofit the boat 1 hull curvature when the driving tidal leg 4 is inposition of use, as shown in FIG. 1. In this way, the L-shaped plate 48a comes to support the boat 1, enabling to lock the driving tidal leg 4in position, together with the threaded rod 42 b-nut 42 c connection.

It can also be seen in FIG. 1 that the driving tidal leg 4 is alsoprovided with floats 49 and that the control device 5 controls theelectric motor 47 of each driving tidal leg 4 using levers 52 andcontrol cables 51 connected to the control device 5 and to the electricmotor 47.

The electric motor 47 is powered either by a battery or the boatbatteries, or by an on-board power generator. The power wires aresecured to the wall of the driving tidal leg 4, for example by stapling.

It is now referred to FIGS. 4A to 4C, showing the three steps foradjusting the kit device of the invention to a specific boat.

Indeed, it is necessary to adjust the device of the invention such that,when the boat is retrieved from water, the wheels 43 of the drivingtidal legs 4 come first into contact with the boat launch slip, beforethe group of free wheels 33, in order to ensure their drive function.

The slope of the boat launch slip can be of 4-6°, particularly of 5° orapproximately of 5°, so as to ensure a good grip of the drive wheelswhen they arrive on the slip while getting out of water.

This is achieved by adjusting the position of the free wheels 33 in thelongitudinal direction of the stem bar 3.

FIG. 4A shows a side view of the boat 1 lying on legs 60, such that itstrue waterline A, which is painted on the boat 1 hull, is horizontal.

The driving tidal legs 4 are then positioned on each side of the hulland the support platform 48 is adjusted so that it leans against thehull in order to support the boat 1 weight.

Then, the stem bar 3 is secured and the slope of the shims 119 isadjusted so that they come into contact with the underpart of the hullfor properly positioning the stem bar 3.

Then, the slope of the boat launch slip of the port which will befrequented is physically represented by a line B, for example by meansof a cord, and the position of the free wheels 33 is adjusted such thatthese wheels 33 are located above this line B, as can be seen in FIG.4B.

When the legs 60 are removed, the boat 1 is in the position for movingon solid ground, which position is shown in FIG. 4C.

These different steps for adjusting the device of the invention areperformed when this device is used for the first time with a specificboat 1. Given that the longitudinal position of the free wheels 33, theslope of the shims 319 and the positions in depth and in height of thesupport platform 48 are not modified when using the device of theinvention, these different adjusting steps are only necessary at thefirst use.

On solid ground, the boat 1 is supported and moved by the device of theinvention. It can be parked in a harbour facility 7, as shown in FIG. 6.

This harbour facility 7 in dry dock, for receiving boats equipped withthe device of the invention, defines a parking area provided withparking spaces 71, an area 72 for receiving boats and a boat launch andretrieval slip 73. The area 72 for receiving boats is an area having aflat surface, enabling the users who arrive at the harbour facility toknow that they are on solid ground, and particularly, that the ground isflat. Therefore, the user can, for example, disengage the pawl 46 inorder to be able to perform a reverse movement.

When the user wants to launch the boat 1 into water, all he/she has todo is control the electric motors 47 using the control device 5 forleading the boat 1 to the boat launch slip 73. The boat 1 is caused torotate on the right by only controlling the electric motor 47 on theport side, and to rotate on the left by only controlling the electricmotor 47 on the starboard side.

The brake device, constituted by the ratchet wheel 45 and the pawl 46,enables to prevent a reverse movement. However, if a reverse movement isnecessary, the user can disengage the pawl 46 from the ratchet wheel 45in order to enable the wheel 43 to rotate in both directions. This canbe particularly necessary for leaving a parking space 71.

Once into water, the user detaches the stem bar 3 and recovers thelatter, which at this time floats on water thanks to the floats 35,using the lines 323, for storing it on board the boat. The user alsodetaches each driving tidal leg 4 and lifts them using the boat launchhandles 42 d.

Then, the user can navigate freely.

When he/she wants to go back to the port, the user, for example whenarriving inside an area delimited by marking buoys and dedicated for themounting/removing of the device according to the invention, attaches thefront end of the stem bar 3 to the end plate 34, then draws the rear endof the stem bar 3 against the keel using the lines 323, in order to lockthe stem bar 3 in position.

Then, the user places the driving tidal legs 4.

Of course, the user can first attach the driving tidal legs 4 and thenthe stem bar 3.

Once the device of the invention in position, the user steers the boat 1so as to drive it on the slip 73 of the harbour facility 7. Thanks tothe adjusting of the device of the invention before the first use, thewheels 43 of the driving tidal legs 4 touch the slip 73 first and theuser can therefore control the boat 1 displacement until the area 72 forreceiving boats by controlling the electric motors 47.

The brake device enables to prevent the boat 1 from reversing in theevent of a breakdown of the motors 47 while the boat 1 is still on theslip 73.

The members constituting the device according to the first embodiment ofthe invention described above are not built into the boat 1, and thusthe user has to attach and detach these different members.

According to a second embodiment, shown in FIG. 5, the sets the deviceof the invention is made up of are built into the boat 100 such that theuser does not have to carry out these mounting and removing operationsany longer.

The first set 120 with free wheel(s) comprises the at least one freewheel or the at least one free wheel group on their own holder, withoutthe stem bar.

The second sets 130 are constituted by the driving tidal legs withoutthe means for gripping them, fitting them to the hull and installingthem against the hull, which have been described with reference to thefirst embodiment.

The boat 100 is provided with a casing 110 enclosing the first set 120and two casings 110 each enclosing a driving tidal leg 130.

The control device (not shown) controls, in addition to the rotation ofthe electric motors of the driving tidal legs 130, extension/retractionmechanisms enabling to extend and to retract the at least one free wheel120 and the driving tidal legs 130 respectively out of and into thecasings.

Once into water, the user, through the control device, causes the atleast one free wheel 120 and the driving tidal legs 130 to be retractedin the corresponding casings 110. When he/she wants to go back to theport, the user causes the at least one free wheel 120 and the drivingtidal legs 130 to be extended out of the casings 110.

The displacement of the boat 100 is identical to the displacement of theboat 1 equipped with the kit according to the first embodiment of theinvention.

Both first and second embodiments of the invention described aboverelate to the use of the device of the invention with rigid-hull-typeboats.

It is referred to FIG. 7, where it is shown a pneumatic-type boat 200,which is equipped with a device according to an alternative of the firstembodiment of the invention. The boat 200 sides are constituted bysponsons 210 connected to the rear area of the boat 200 by a rear panel220 holding an engine 230.

The device according to this alternative includes a stem bar 300, twodriving tidal legs 400 and a control device 500.

The stem bar 300 is identical to the stem bar 3 of the device accordingto the first embodiment of the invention, except for the fact that itsfront portion is bended for fitting the hull of such a boat.

It is now referred to FIG. 8, where it can be seen that the drivingtidal leg 400 differs from the driving tidal leg 4 according to thefirst embodiment by the fact that it is not provided with a supportplatform 48 and it is not secured on the lateral sides of the boat.Indeed, the sponsons 210 being pneumatic, the driving tidal legs 4according to the first embodiment cannot be secured in the way describedabove.

Consequently, the driving tidal leg 400 is secured to the rear panel 220of the boat 200, on each side of the engine 230.

The support platform 48 is replaced with a connection block 401, asupport block 402 and a bearing piece 403.

The moving body 420 of the leg 400 has, on each side thereof, threadedholes 421 arranged in a column.

The connection block 401 is provided with a column of through holes 401a and the support block 402 is also provided with a column of throughholes 402 a.

The connection block 401 and the support block 402 are secured to themoving body 420 by two bolts 404 respectively passing through a throughhole 401 a and a through hole 402 a to each be screwed in a threadedhole 421.

Arranging the threaded holes 421, the through holes 401 a and thethrough holes 402 a in column enables to adjust the position of theconnection block 401 and of the support block 402 in height in order toadapt the leg 400 arrangement to the specific configuration of the rearpanel 220.

Each leg 400 is secured to the rear panel 220 by a bolt 405 passingthrough a through hole 401 b made in the connection block 401.

The shear strength of the bolt 405 not being sufficient to bear thestress exerted by the boat weight, it is provided that the bearing piece403 is secured to the rear panel 220 by two screws 403 b passing throughthrough holes 403 a made in the piece 403 and coming to be screwed intwo threaded holes of the rear panel 220.

The bearing piece 403, coming in the form of a rectangular-shaped plate,includes an area 403 c protruding from a first surface of the plate,thereby creating a shoulder, the end face of the protruding area 403 cbeing intended to lean against the rear panel 220 once the bearing piece403 has been secured to the boat 200.

The support block 402 has, on its upper edge, a groove 402 b which canreceive the shoulder of the bearing piece 403.

Thus, the position of the support block 402 in height is adjusted withrespect to the moving body 420 such that, once the leg 400 has beensecured to the rear panel 220, the bearing piece 403 comes to press onthe support block 402. This enables the leg 400 to bear the boat 200weight.

The boat 200 is launched into water and retrieved from water and thedevice of the invention is adjusted and removed in the same way as theone described above for rigid-hull-type boats.

The displacement of the boat 200 is also identical to the displacementof the boats 1 and 100 equipped with the device according to the firstembodiment and the second embodiment of the invention, respectively.

It is also to be noted that it is possible to add to the boat membersenabling to warn third parties about a boat manoeuvre, for example aflashing light or a siren, particularly in the event of a reversedisplacement of the boat in the harbour facility.

It can further be provided that the lines 323 connected to the stem bar3 and the floats 49 of the driving tidal legs 4 be red-coloured for theport side and green-coloured for the starboard side, such that theperson on board the boat knows what line 323 he/she has to secure on theport side and what line he/she has to secure on the starboard side, andlikewise for the two driving tidal legs 4.

With reference to FIG. 9, the boat 200 is equipped with a curved-shapeone-piece stem bar 300′ which is an alternative implementation of thestem bar 3, 300. The free wheels 32 are mounted on the stem bar 300′ inthe same way as the one shown in FIG. 2. The stem bar 300′ is appliedagainst the stem and maintained in this position is the same way asdescribed above for the stem bar 3, 300. The stem bar 300′ is providedat the rear with shims 319 fulfilling the same function than the shims319 of FIG. 2, and, at the front, it is hingeable between two parallelears 250 formed at the front of the boat.

It is now referred to FIG. 10, where it can be seen a tidal leg 4′ thatis made substantially like the tidal leg 4 of FIG. 1 and the composingparts of which are designated by the same reference numbers, with thedifference that it includes two wheels 43 instead of one wheel, thewheels 43 being mounted on the same axle and provided on both sides ofthe body 42 that is here made of a single part, in order to ensure abetter balance of the tidal leg.

The leg 4 of FIGS. 1 and 8, the body of which is in two parts, couldalso be equipped with two wheels 43 instead of one wheel.

It is now referred to FIGS. 11 and 12, where it can be seen an exampleof a device for mounting the tidal leg on the boat hull which has theadvantage of not requiring the drilling of a hole in the hull.

To this end, a bracket 50 is placed on the edge of the boat hull. On theouter face 50 a of the bracket is secured, via screws 51, a plate-shapepart 52 carrying a horseshoe-shaped protuberance 52 a opening downwards.The body 42 of the tidal leg 4 is extended at its upper portion by asmall plate 42 h carrying on its face facing outwards a lug 42 i, whichis caused to be caught in a housing provided behind an overhangingportion 52 j at the upper portion of the horseshoe-shaped protuberance52 a, the small plate 42 h being caused to be positioned in the innerspace of the protuberance 52 a in the mounted position. A cover 53 isthen positioned over the plate-shaped part 52—small plate 42 h assemblyin the mounted position. The cover 53 has a cut-out 53 a for lettingpass the overhanging portion 52 j.

The water launch handle 42 e carried by the cover 53 has not beendepicted on FIGS. 11 and 12.

It is now referred to FIG. 13, where it can be seen a stem bar 3′ inaccordance with an alternative to the stem bar 3 of FIG. 1, the partscommon to both stem bar being designated by the same reference numbers.

The difference between the stem bars 3 and 3′ lies in the fact that thestem bar 3′ is formed by a series of flat links 3′a hinged one toanother along an axis 3′b. In the illustrated example, one link 3′aevery two links is folded back along its two free borders to form twowings 319. The last link 3′c, on which the free wheels 33 assembly ismounted, is longer than the other links and has two wings 319 on bothsides.

This implementation with a chain of links allows a good adjustment ofthe stem bar 3′ to the stem of the boat.

The stem bar 3′ may also be advantageously used on pneumatic-type boats.

The disclosed device, several embodiments of which are described above,enables an easy displacement of a grounded boat. It is thereforeconceivable to create temporary harbour facilities, particularly duringsummer when the traffic is very important, by temporarily installingboat launch and retrieval slips.

The harbour facility can also be provided with trailer parking spaces,such that, if the owner of the boat does not want to leave his/her boatin the harbour facility throughout the year, he/she can secure the boatto the trailer conveniently and tow the boat using a vehicle, as wellknown.

It is also contemplated that the boat be driven on the road using thedriving tidal legs, which enables to avoid using a vehicle and atrailer.

Of course, the embodiments which were described above were given as anindication and in a non restrictive way and modifications can be madewithout departing from the spirit and scope of the invention.

1- A device to be mounted on a boat to enable to launch and to retrievethe boat from and into water through a boat launch and retrieval slipand to drive it on solid ground, wherein it comprises: a first setconstituted by at least one freely pivotable wheel or group of freelypivotable wheels mounted on a holder to be mounted in the stem area ofthe boat; and two second sets each constituted by at least one drivewheel mounted on a holder to be mounted in the rear area of the boat,with one of the second sets on the port side and the other on thestarboard side, said sets being arranged so that, when they are mountedin the stem area and on the port side and on the starboard side,respectively, the at least one free wheel in the front and the drivewheels in the back are placed on the ground, in order to make the boatroll on solid ground and to launch and retrieve it from and into water,said sets being adjustable so that, when the boat is retrieved fromwater, the drive wheels come into contact with said slip before the atleast one free wheel, said sets being further retractable in order toleave the boat hull free for navigation, means being provided for thecontrol of the drive wheels. 2- Device according to claim 1, wherein theholders of the first set and second sets each are provided, on the onehand, with adjustable mounting means on the outside of the boat hull,which is provided with complementary means for receiving said holders,and, on the other hand, with means enabling the user to remove each ofthe sets from the boat once the latter has been launched into water andto bring them back into the boat, and then to mount them again from theboat in preparation for the arrival on the slip leading to solid ground,the holder of the first set consisting in a so-called stem bar, which isto be positioned along the boat stem line, which may go down to thekeel, and fit the stem curvature, and to which is connected a pivot axisof the at least one free wheel, and the holder of each second setconsisting in a so-called tidal leg carrying at its base its associatedat least one drive wheel. 3- Device according to claim 2, wherein theholder of the first set comprises means for damping the boat weight onthe at least one free wheel and the holder of each second set comprisesmeans for damping the boat weight on the at least one drive wheel. 4-Device according to claim 2, wherein the first set and/or the secondsets are provided with at least one float so as to float into water. 5-Device according to claim 2, wherein the stem bar includes a front barand a rear bar which are pivotable with respect to each other so as tofit the boat stem curvature by extending down to the keel, at least oneof the bars being adjustable in length so as to adapt to the boat sizes,at least one of the bars being edged by shims in order to better fit thestem shape. 6- Device according to claim 2, wherein the stem bar isformed by a chain, consisting in successive flat links hinged one toanother, at least one flat link being foldable along its free borders inorder to form shims allowing to better fit the shape of the stem. 7-Device according to claim 2, wherein the stem bar consists in acurved-shape one-piece bar, whose curve fits the stem curve of the boatto be equipped with the device. 8- Device according to claim 2, whereinthe stem bar has means for adjusting the longitudinal position of the atleast one free wheel, allowing to adjust the position of the at leastone free wheel such that, when the boat equipped with said devicearrives on a boat retrieval slip, the drive wheels of the tidal legsfirst touch the boat retrieval slip. 9- Device according to claim 2,wherein the stem bar is provided, at its stem side end, with a means forsecuring the stem bar to the boat, as well as with a handle that theuser can grip to bring the stem bar back on board, and is provided with,at its keel side end, at least one passage for at least two lines or atightening strap for maintaining the stem bar against the stem. 10-Device according to claim 2, wherein each leg includes: a fixed body; amoving body moveable with respect to the fixed body for damping theuneven ground when the boat rolls on solid ground, and provided withbearing means arranged to support the boat; the at least one drive wheelconnected to the fixed body; an engine driving the at least one drivewheel and controlled by said control means; securing means for securingthe driving tidal leg to the boat; and at least one carrying and/orgripping handle for the boat launch. 11- Device according to claim 10,wherein it includes, associated to the engine, a braking device. 12-Device according to claim 10, intended to be used with rigid-hull-typeboats, wherein: the legs are arranged to each be placed on a lateralside of the boat hull, symmetrically with respect to the longitudinalmedian plane of the boat; the bearing means are constituted by a supportplatform leaning against the boat hull when the device is in mountedposition, in order to support the boat, the position in height and indepth of the support platform with respect to the moving body beingadjustable so as to fit to the hull curvature; and the means forsecuring the leg to the boat are constituted by a threaded rod extendingfrom the leg and passing through a hole made in the boat hull andcooperating with a nut in order to lock the driving tidal leg againstthe boat hull. 13- Device according to claim 10, intended to be usedwith pneumatic-type boats, sides of which are constituted by sponsorsconnected by a rear panel carrying an engine, wherein: the legs arearranged to be secured to the rear panel, on each side of the engine;the bearing means are constituted by a bearing piece secured to the rearpanel and comprising an area protruding from a first surface of thebearing piece in order to create a shoulder, the end face of theprotruding area coming into contact with the rear panel in the mountedposition, and by a support block which is secured to the leg moving bodyand having, on its upper edge, a groove receiving the shoulder of thebearing piece in order to support the boat; and the means for securingthe leg to the boat are constituted by a connection block to be securedto the moving body and provided with a threaded hole receiving a boltpassing through a through hole made in the rear panel in order to securethe connection block to the boat, the position in height of theconnection block with respect to the moving body being adjustable. 14-Device according to claim 1, wherein the first set and the two secondsets are built into a boat and are retractable in casings formed in thehull, said sets being provided with means for mounting their holders insaid casings and means for controlling their extension out of saidcasings so as to position the wheels in a position for making the boatroll on solid ground and for launching and retrieving it from and intowater, and their retraction in the casings to leave the boat hull freefor navigation. 15- Device according to claim 1, wherein the means forcontrolling the drive wheels are hand-held control means or controlmeans applied to the instrument panel. 16- Boat equipped or ready to beequipped permanently with the device as defined in claim
 14. 17- Methodfor initially adjusting the device according to claim 1, wherein itcomprises the following steps: the boat is placed on legs such that itstrue waterline, which is painted on its hull, is horizontal; the secondsets and the first set are positioned on the boat; the slope of the boatlaunch slip of the harbour facility is physically represented by a lineB, for example using a cord; the height of the drive wheels and of theat least one free wheel are adjusted with respect to this line B toensure that the drive wheels will come into contact with the slip beforethe at least one free wheel. 18- Harbour facility for receiving boatsequipped with a device as defined in claim 1 and boats as defined inclaim 16 in order to allow parking thereof, said harbour facilitycomprising a boat launch and retrieval slip leading to a boat groundparking area, the slip having a slope for which the means for drivingthe boats were adjusted so that the drive wheels of the rear drive meanstouch the boat retrieval slip first, said harbour facility alsocomprising an area for receiving the boats once they have been retrievedfrom water. 19- Harbour facility according to claim 17, wherein the slipslope is of 4-6°, in particular of 5°.